Agata Łącka

The use of transglutaminase in the reduction of immunoreactivity of wheat flour

Abstract The immune response of wheat flour modified by the treatment with transglutaminase under different conditions of temperature, incubation periods and the ratio of enzyme/wheat flour was investigated. The particular wheat protein fractions were examined for the immune reaction by the use of an indirect non-competitive ELISA. Commercially available antibodies, namely, monoclonal antihuman IgG and monoclonal antihuman IgE conjugates with alkaline phosphatase and human sera with elevated IgG as well as rabbit sera against QQQPP peptide were tested. The highest decrease in gliadins immunoreactivity was observed for wheat flour modified under following conditions: temperature 37°C, 18 h of incubation and the ratio enzyme/wheat flour 1:10 000. For all rabbit sera examined the residual immunoreactivity of glutenins was found to be below 30% of the level measured for the untreated protein. The large decrease in allergenicity of glutenins leads to the conclusion that wheat flour modified by treatment with transglutaminase may be used as a constituent of food products destined for people with a classic food allergy, i.e. the allergy elicited by that protein fraction.

Decrease of wheat flour allergenicity via lactic acid fermentation

Abstract Results of the research on the lowering of allergenicity of wheat flour fermented using homo- and heterofermentative lactic acid bacteria and mixed cultures with yeast were discussed. The gliadins’ immunoreactivity was measured using the indirect non-competitive enzyme-linked immunosorbent assay method. The biggest decrease of the immunoreactivity of gliadin fraction was observed in the case of fermentation performed with the use of mixed cultures of lactic acid bacteria and yeast. This way of wheat flour modification seems to be promising, because fermentation is a natural process causing not only lowering of the allergenicity, but also improving organoleptic and nutritional values of obtained products.

The effect of enzymatic modification and genetic background on wheat gliadin immunological properties

Abstract The immune response to gliadins extracted from 35 wheat cultivars, strains and species was investigated. With the use of a non-competitive ELISA method, we sought to examine if immune reaction occurs between wheat proteins and sera from patients sensitive to gluten, as well as between wheat proteins and rabbit antibodies against pentapeptide QQQPP. Results showed considerable differences among cultivars. Breeding strains STH 183, STH 650, STH 2804, Triticum aethiopicum and Triticum durum showed the lowest immunoreactivity of the native samples. Seventeen of selected wheat flour samples were subjected to enzymatic modifications by subtilisin and transglutaminase. Samples modified by subtilisin exhibited the most extensive change in the level of immunoreactivity of gliadin proteins. The lowest immunoreactivity was reported for the breeding strains STH 1596, STH 2804 and cultivars Tonacja and Zyta. One wheat cultivar (Tonacja), known for its high native gliadin immunoreactivity, was shown to be very susceptible to enzymatic digestion, which resulted in a reduction of its initial immunoreactivity level to low values. Immunoreactivity analysis was also conducted on extracted gliadin fractions from winter wheat strain Ostka strzelecka. The highest level of immunoreactivity to both types of antibodies we used was indicated for ω5-gliadins. It was, however, abrogated in the aftermath of enzymatic modifications.